In the multiverse, pocket universes could be born with clashing directions of time – the evolving future of one could happen in the rewinding past of another

Quote

By Joshua Sokol

DON’T pity those in the past – in their own way, they might have a lot to look forward to. From our perspective, events in some universes may seem to unfold backwards. That implies there could be alternate worlds whose future is actually even further in our distant past.

This trippy idea has been suggested before, often with very specific caveats. In 2004, Sean Carroll, now at the California Institute of Technology in Pasadena, showed it could apply, but only if complex and unlikely physics was involved.

Now Carroll and cosmologist Alan Guth of the Massachusetts Institute of Technology have shown how time itself can arise organically from simpler principles, then flow in opposite directions in adjacent universes.

.

Guth and Carroll’s work is motivated by a problem vexing physicists and philosophers: why it is that time’s arrow points in just one direction. It’s true we can only remember the past (see “Why the future keeps slipping your mind“), but the laws of physics don’t much care which way time flows: any physical process run backwards still makes sense according to those laws.

“There’s no such thing, at a very deep level, that causes [must] precede effects,” says Carroll.

In the absence of other laws to set the direction of time, physicists have settled on entropy – basically, a measure of messiness. As entropy grows, time ticks forward. For example, you can stir milk into coffee but you can’t stir it back out again – so neatly separated black coffee and milk always comes first.

“We can’t talk to beings in a time-reversed cosmos: they are in our past and we in their past”

Zooming out to the entire universe, we likewise define the future as that direction of time in which entropy increases. By studying the motion of faraway galaxies, we can predict how the cosmos will evolve. Or we can rewind time back to the big bang, when the universe must have had much less entropy.

Try to rewind further and we meet a cosmological conundrum. We can’t proceed if the big bang was indeed the beginning of time, but in that case, why did it have such low entropy? And if it wasn’t the beginning of time – as Guth suspects – we’d still want to know how an eternal universe could have reached such a low-entropy state that would allow for the arrow of time to form.

In an as yet unpublished model, Guth and Carroll explore the latter idea. They drop a finite cloud of particles, each zipping around with its own randomly assigned velocity, into an infinite universe. After a while, arrows of time emerge spontaneously.

The random starting conditions mean that half the particles initially spread outwards, increasing entropy, while the other half converge on the centre, decreasing entropy, then pass through and head outwards. Eventually the whole cloud is expanding, and entropy is rising in tandem. Crucially, this rise happens even if you reverse time by flipping the starting velocity of every particle: ultimately, all particles will end up travelling outwards. If entropy grows either way, who’s to say which way the arrow of time should point?

“We call it the two-headed arrow of time,” Guth says. “Because the laws of physics are invariant, we see exactly the same thing in the other direction.”

The model shows that an arrow of time arises spontaneously in an infinite, eternal space. Since this allows entropy to grow without limit, time zero could simply be the moment where entropy happened to be at its lowest.

Quote

That could explain why the big bang, the earliest moment we can see, has so little entropy. But it also feels a little like a cheat: if entropy can be infinite, anything can have relatively “low” entropy by comparison.

“The point that Alan and I are trying to make is that it’s very natural in those circumstances that almost everywhere in the universe you get a noticeable arrow of time,” Carroll says, though he admits the model still needs work. “Then of course you do the work of making it realistic, making it look like our universe. That seems to be the hard part.”

If the model matches reality, it would have implications for more than just our own observable universe. “This is intended to describe the whole of existence, which would mean the multiverse,” Guth says. In his view, the arrow of time may have arisen in a parent or grandparent universe of our own.

According to cosmic inflation – an account, pioneered by Guth, of the universe’s rapid early expansion – our cosmos is just one among many. Fresh pocket universes, next to ours but far enough away as to be unreachable, spring from the vacuum all the time.

That would mean that the big bang represents the instant our universe sprang into being from the multiverse, after the arrow of time had already been set.

Parallel universes, born around the same time as ours, would have started with similar entropy to ours. If we could talk with beings there, they would agree with us on the direction of past and future.

But from our viewpoint, time would be turned on its head in universes that arose before our arrow of time was set (see diagram). Nobody would notice, though. While small, random differences between these backwards universes and ours might lead to vastly different fates, living beings there would see an arrow of time, but “to them we would be in the past and we would have the wrong arrow of time direction”, Carroll says. It would be hard to have that argument though. “We can’t talk to them; they are in our past. And they can’t talk to us, because we are in their past,” he says.

(Image: Jaak Nilson/Blend/Alamy)

The new model has its issues. Its initial state, when all particles are given random velocities, is fuzzy in that the diverging arrows of time are not yet clearly defined, since entropy is growing in some places while shrinking in others.

Understanding this period in between the two emergent arrows of time is hard. “That nebulous region in the middle might turn into a real monster,” says Andreas Albrecht at the University of California in Davis.

It’s a weakness Guth acknowledges – and along with the difficulty of incorporating elements like gravity, it’s a reason why their work hasn’t been published yet, he says.

“The direction of time we experience could have been set in a parent or grandparent universe”

“What we’d like to understand better is how to describe this middle region,” Guth says. “But all of physics is described in terms of a system where the arrow of time is well defined, so it’s a stretch to figure out how physics would behave.”

Albrecht also isn’t sold on how the model handles an infinite universe, in which entropy can just keep growing forever. That key feature explains why the big bang had “low” entropy compared with now, but it’s controversial.

“They’ve created a world where they can slip certain notions in very easily,” Albrecht says. He believes their use of infinite universes helps to hide big assumptions in the model.

But Albrecht likes the possibility of two arrows of time, where the multiverse’s distant past is also its far future. “The double-headedness is something I totally embrace,” he says.

Remember to keep your past and future in the proper order. Although the laws of physics don’t care if you live backwards in time, natural selection might.

Heinrich Päs of the Technical University of Dortmund, Germany, and his team modelled the lives of “agents” trying to dodge falling rocks within a two-dimensional grid. “We have something like sex and violence. The rocks kill the individuals, and the individuals breed,” Päs says.

Each rock bounces off the grid’s walls like a ball on a billiard table. To give the simulation an arrow of time, rocks break in half on hitting a wall, which increases entropy, a measure of time’s flow (see main story). If an agent is about to get hit by a rock, they have some chance of stepping out of the way, but they can only avoid one at a time. If two are incoming, they will certainly be hit, draining their “health” by an amount determined by the size of the rock.Stay safe, look ahead

Päs’s team ran the simulation with agents that look either forwards in time or backwards, against entropy. They found that agent populations grew better when they saw time run forwards (Journal of Modern Physics, in press). That’s because when time runs forwards, agents only have to predict the split of one rock to stay safe. When it runs backwards, they must track many little rocks coming together into one.

That’s not too surprising, says James Hartle of the University of California in Santa Barbara. It has been shown that laying down memories involves an overall increase of entropy. By contrast, systems with unchanging entropy, like a frictionless swinging pendulum, can’t act as memory stores. So of course memories can only come from the past, Hartle says.

Still, Päs thinks the potential evolutionary benefit of mentally tracking entropy’s increase might help shape the way we perceive the past and future. “It looks like a crazy idea to use some scenario of evolution to explain some very basic property of time itself,” he says. “The point is more that you really can do it.”

This article appeared in print under the headline “Time itself goes back to the future”

Did the Big Bang create a 'mirror universe' where time moves BACKWARDS? New theory could explain our past - and our future

Scientists have proposed a radical new theory of time for the universe UK physicist Dr Julian Barbour and others say there are two arrows of time These move in opposite directions and both formed at the Big Bang This means at the Big Bang there were two universes that formed Observers in either universe would view the other as moving backwards

By Jonathan O'Callaghan for MailOnlinePublished: 10 December 2014

Quote

The inexorable tick of time moving forward is something that has puzzled scientists for more than a century.

But now a new theory has been proposed that may help answer some questions - at least with regards to the beginning of time and what happened in the 'past'.

They say that at the moment of the Big Bang a 'mirror universe' to our own was created that moves in the opposite direction through time - and intelligent beings in each one would perceive the other to be moving backwards through time.

Since the Big Bang the universe has given rise to planets, stars and galaxies (illustration shown) as time ticks forward and matter clumps together. But a new theory suggests that at the same time a second universe is moving in the opposite direction, with a 'backwards' arrow of time to us

Quote

The radical theory was proposed by Dr Julian Barbour of College Farm in the UK, Dr Tim Koslowski of the University of New Brunswick in Canada and Dr Flavio Mercati of the Perimeter Institute for Theoretical Physics, also in Canada.

Their research attempts to answer questions that remain about the ‘arrow of time’ - which is the concept that time is ‘symmetric’ and everything moves forwards.

They say that at the time of the Big Bang not one but two universes formed – both moving equally in each direction through time, but opposite to each other.

‘Time is a mystery,’ Dr Barbour told MailOnline. ‘Basically, all the known laws of physics look exactly the same whichever way time runs, and in the world in which we live everything goes in one direction.

The new research attempts to answer questions that remain about the ‘arrow of time’ – which is the concept that time is ‘symmetric’. They say that at the time of the Big Bang not one but two universes formed – both moving equally in each direction through time, but opposite to each other, like two one way systems

Quote

‘The universe is expanding, we get older, the order seems to grow - at least in our immediate vicinity.’

Dr Barbour gives the analogy of an ice cube melting in a glass of water as the universe moving from structure to disorder - known as entropy.

He says at the end of the 19th century this caused concern - as people thought the universe would end in a ‘heat death’ where the temperature in the universe was the same everywhere, just like the ice cube.

But when gravity is taken into account it seems the theory no longer holds true - and it may also explain a dramatic start for the universe.

Lee Billings, writing for Scientific American, said: ‘Thus, the sheer force of gravity sets the stage for the system’s expansion and the origin of time’s arrow.’

By assembling a simple model with 1,000 particles, the researchers say their theory shows that as you move backwards through time - to disorder - you eventually come out the other side after the Big Bang in order again - a ‘mirror’ universe.

While time moves forwards for us, intelligent beings in the 'mirror universe' would think that we are actually moving backwards. However, we would both have come from the same beginning - the Big Bang. It should also be noted that the universes are not identical, but simply time-symmetric

Quote

This universe would not be exactly the same as ours, though; it would have evolved and changed in its own way, completely separate to our own.

However, it would be subject to the same laws of physics, so it would likely have planets, stars and galaxies just like in our version of the cosmos.

Explaining the model as a swarm of bees, Dr Barbour says that as time increases, the universe moves from an initial chaotic ‘swarm of bees’ to a more structured and ordered cosmos.

‘If you look at a simple model with a swarm of bees in the middle [the Big Bang] but breaking up in either direction, then you would say there are two arrows of time, pointing in opposite directions from the swarm of bees,’ he said.

‘One arrow would be forwards, and one backwards.

‘If you define time as the direction in which order is increasing, you always get two arrows in opposite direction from the central chaotic region.’

He continued that it is opening up a new way to think about the Big Bang.

‘At the moment when people talk about the Big Bang, they more or less throw their hands up in despair and say they can’t say what happened.

‘Now our work is beginning to suggest we can actually say more than people thought.’

I have never bought into the Big Bang theory, (or the creationism doctrine, and I do apologies to anyone on here who is religious) - neither story rocks my boat -

Are we really supposed to believe that the expanding universe was created from nothing ?

I would think it more likely that our universe may well have collided with another universe or had multiple collisions and brushes with other universes and dimensions in the course of its history.

Kaku talks of 11 dimensions at the moment -

Not something I can imagine, or visualise, or even attempt the advanced mathematics at btw -

With respect to time, I do believe it is a human construct, and it exists because as a "modern" species we seem to require boundaries and hard terms of reference.

(I do wonder what the tribes of the Amazon and Papa New Guinea use? or if they have a concept of time ? I would love to know if any of you folks have info on that ?)

Scientist do not seem to be able to explain a lot about the universe that they CAN observe, and I don't think they have a coherent theory on dark energy / dark matter at the moment? I could be wrong and a quick look at Google Scholar shows a lot of theory on the subjects.

Which then brings me full circle to the simulation / holographic universe hypothesis I mentioned on another thread - it stands to reason that not every scientist and classical theory can be correct ..

So I am standing (alone most likely) in the Universe / Multiverse Colliding part of the room and incorporated in that, I really believe that we (humans) are all part of some giant simulation.

Are we really supposed to believe that the expanding universe was created from nothing ?

The Big Bang theory doesn't say that. In fact, the Big Bang theory is not about how the universe appeared, is about how the universe behaved from a specific hypothetical situation in which the universe was extremely small, dense and hot.

Time is just a measure of transmutation, and the so called big bang was just a pinch point for our existence from one segment of reality to another, like a 8 track switching programs, it seems big and bangy (lol) but all it is is reality and existence emerging from a compression point which we are currently headed for.

Breathing does suggest a forward and backward movement of "time" but not simultaneous movement of both, which clearly would cancel out one another, creating a guarantee of paradoxes which manifest as incurable illness or purely non homestatic state.

One step forward, two steps back.

As for CMB radiation, all transmutation leaves fingerprints of the previous "incarnation" and the apparent CMB radiation is just a measure of density of current reality, and the programmer of geometric and electromagnetic fields which our reality is immersed in.

So, this CMB has a use, whereas it holds all past present and future information required to reach continuity of universe, and the apparent recording of that information as transmutation occurs is time.

Some call it the Akashic Record...others an operating system.

Creationists and religious people struggle to find a shred of evidence in all of this to explain their bronze age invented belief system, scientists try too hard to muddy the waters with elaborate unnecessary theories and mathematics, but the universe we are in doesnt care, as it is just a miniscule point in a far greater, timeless reality.

Does one listen to the single cell which warns of cancer? No, it requires a message of significance, as in a tumor or growth, which describes the period we are transmuting through now most likely.

When the sentience that we are a part of transmutes fully from pure entropy-less energy, through our "Time" and back to a compressed, fully non- entropic state, all we perceive, know or observed will be reordered to expand back to a progression toward pure entropy, at an immeasurable non-point and then timelessly launched into our next manifestation of the sentience that is our "God".

This means, we move forward in time until pure entropy, then at the point where we seem to have exhausted all possibilities, we begin to move back towards pure non entropy, which some may perceive to be moving backward in time.

As a boy I asked my mother.." if we could travel to the edge of the universe, and find that edge, what would be on the other side of the edge, and how could a universe end, if it supposed to be infinite?

Needless to say she sent me to church, and I then found the worst possible approach to reality, was to subscribe to something as ludicrous and insane as religion.

I have sought out the truth ever since, and been through some bizarre and unique idea and theories in search of that understanding, with no need for any human convention such as narrow minded science, or deity based belief systems.

I may be right, partially right, or completely wrong, but the information I have based my thoughts on here, is from an unerasable hard drive, the true source of our little piece of reality's infinity.

Le... I don't quite understand equating a gas exchange with forward and backward movement. That's from a nursing perspective. Personally, I think time as linear, is an artificial construct that we've imprisoned ourselves in. That could be a nursing perspective too, I guess, based on the number of clock watching patients I've dealt with over the years. " My pain pill is three minutes late!"

Le... I don't quite understand equating a gas exchange with forward and backward movement. That's from a nursing perspective. Personally, I think time as linear, is an artificial construct that we've imprisoned ourselves in. That could be a nursing perspective too, I guess, based on the number of clock watching patients I've dealt with over the years. " My pain pill is three minutes late!"

Shasta

I agree. Time is a human construct to manage life and history. We see it as linear, but it isn't.

Transmutation is much more than a gas exchange, it is the process where one element becomes another through various means, yes, but it is the intent of the transmutation which implies sentience here in this universe.

Although you did make me snicker a bit when I read gas excahnge...

Picture a tapestry, between two rings, pinched tightly at the rings, but billowing in the middle...the rings are the "big bangs" and the rest is expansion and compression of our very existence, hence time which slows and accelerates relative to our position along the tapestry.

Infinity is a great symbol to describe it in simpler terms...as is Uroboros.

Time may be linear if we extract a segment of the timeline, but as a whole it is a perfectly balanced series of transmutative events which are cyclical in nature...like observing one part of a sine wave on an o scope, but not the entire wave itself...which is time.

Therefore it is a measure of elemental transmutation, and relocation of all we perceive to a single immeasurable point, which is the ring...

The ONLY reason that we are even aware of glitches in time is because a part of us exists OUTSIDE of normal space time... Call it soul, spirit, life force, whatever but because of this we can sense that there are issues with time

What I find interesting is that it appears to be accelerating... more people aware of it, despite all the trolls and debunkers

The thing about infinity is it works in other directions too We are all aware of parallel dimensions but what if we are just molecules in a larger universe?

Breathing does suggest a forward and backward movement of "time" but not simultaneous movement of both, which clearly would cancel out one another, creating a guarantee of paradoxes which manifest as incurable illness or purely non homestatic state.

The paradoxes of time have always been an issue...

If I go back before i was born and kill my father, I would not exist and therefor not be able to go back in time and kill my father

The other side says if i do that I merely create a NEW timeline from that point (as they used in Back to the Future)

Then we have the LOOKING GLASS technology. This is a real project at Los Alamos where they have developed special mirrors that can see light rays that are traveling backwards in time and thus allows them to see possible futures. The Russians were working on similar mirrors. "Phase Conjugation" is the key term. I had a paper that was still classified from the us Army that was working on using this to predict where bullets would come from before they were fired. I checked with a spook at ATS if I was allowed to have that paper. He was surprized by it, had never heard about it... but he did clear it for me.

Yes there ARE real spooks at ATS This one is very open mfluder US Army CointelPro and he has proof